1. Field of the Invention
The present invention relates to a motor vehicle steering system.
2. Description of Related Arts
There is proposed a motor vehicle handle position correcting device that corrects deviation between the position of a handle (the position of a knob in the circumferential direction of a handle wheel) and a tire turning angle in a so-called steer-by-wire system in which mechanical joining between a handle and steered wheels is cut off (for example, refer to Patent Document 1 listed below).
There is also proposed a steer-by-wire motor vehicle steering system that performs steering by using a joystick (for example, refer to Patent Document 2 listed below).
There is also proposed a steer-by-wire steering system that detects the position of a driver's hand gripping the steering wheel and corrects a steering reaction force of the steering wheel according to the position of the driver's hand (for example, refer to Patent Document 3 listed below).
There is also proposed an industrial vehicle power steering system that detects gripping on a knob by using a proximity switch or a touch switch (for example, refer to Patent Document 4 listed below).    Patent Document 1: Japanese Published Examined Patent Application No. 3991632 (Eleventh to twelfth paragraphs and 71st to 76th paragraphs of the specification, and FIG. 7 and FIG. 13)    Patent Document 2: Japanese Published Examined Patent Application No. 3883107 (Third to fifth paragraphs and 158th paragraph of the specification, and FIG. 18)    Patent Document 3: Japanese Published Unexamined Patent Application No. 2007-253640 (28th to 30th paragraphs of the specification, and FIG. 3 and FIG. 5)    Patent Document 4: Japanese Published Unexamined Utility Model Application No. S63-37381 (FIG. 1 and FIG. 3)
Generally, in a cargo-handling vehicle such as a forklift truck and a vehicle for handicapped, to enable a handle (steering wheel) operation by one hand, a rotatable knob is provided on a handle. For example, in a cargo-handling vehicle, a driver performs a handle operation by gripping the knob by his/her left hand while performing a lever operation for a cargo-handling operation by his/her right hand.
The driver may frequently exchange the handle and the knob and operate the handle and the knob in a switching manner, and in this case, a proper steering reaction force is demanded regardless of exchange.